165649920 has 80 divisors (see below), whose sum is σ = 529586640. Its totient is φ = 44171264.

The previous prime is 165649903. The next prime is 165649987. The reversal of 165649920 is 29946561.

It is a happy number.

165649920 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3105 + ... + 18464.

It is an arithmetic number, because the mean of its divisors is an integer number (6619833).

Almost surely, 2^165649920 is an apocalyptic number.

165649920 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 165649920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (264793320).

165649920 is an abundant number, since it is smaller than the sum of its proper divisors (363936720).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

165649920 is an equidigital number, since it uses as much as digits as its factorization.

165649920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21595 (or 21579 counting only the distinct ones).

The product of its (nonzero) digits is 116640, while the sum is 42.

The square root of 165649920 is about 12870.5058175660. The cubic root of 165649920 is about 549.1998502666.

The spelling of 165649920 in words is "one hundred sixty-five million, six hundred forty-nine thousand, nine hundred twenty".